/*
 * Copyright 2017 - 2025 the original author or authors.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see [https://www.gnu.org/licenses/]
 */

package infra.web.socket;

import org.jspecify.annotations.Nullable;

import java.util.List;

/**
 * An interface for WebSocket handlers that support sub-protocols as defined in RFC 6455.
 *
 * @author Rossen Stoyanchev
 * @see WebSocketHandler
 * @see <a href="https://tools.ietf.org/html/rfc6455#section-1.9">RFC-6455 section 1.9</a>
 * @since 4.0
 */
public interface SubProtocolCapable {

  /**
   * Return the list of supported sub-protocols.
   */
  @Nullable
  List<String> getSubProtocols();

}